System configured for applying multiple modifying agents to a substrate

ABSTRACT

The present invention is related to the modifying of substrates with multiple modifying agents in a single continuous system. At least two processing chambers are configured for modifying the substrate in a continuous feed system. The processing chambers can be substantially isolated from one another by interstitial seals. Additionally, the two processing chambers can be substantially isolated from the surrounding atmosphere by end seals. Optionally, expansion chambers can be used to separate the seals from the processing chambers.

CONTRACTUAL ORIGIN OF THE INVENTION

This invention was made with U.S. Government support under Contract No.DE-AC07-94ID13223, now Contract No. DE-AC07-99ID13727 awarded by theU.S. Department of Energy. The U.S. Government has certain rights in theinvention.

FIELD OF THE INVENTION

The present invention is related to systems configured for modifyingvarious substrates with multiple modifying agents.

BACKGROUND OF THE INVENTION

Methods have been developed for the coating or modification of varioussubstrates including textile yarns, fibrous materials, filaments, andthe like. For example, polystyrene is known to be a good coating forglass optical fibers to increase durability. These coatings, however,are generally applied in a variety of ways with chemical treatmentprocesses. Some of these methods of chemical treatment (for coating,impregnation, surface modification, etc.) include solvent-based systemsand melt-based systems.

Solvent-based chemical treatment systems can include organic orinorganic materials in solutions such as aqueous solutions wherein theorganic or inorganic material is dissolved, suspended, or otherwisedispersed in the solution. In the area of coating of glass fibers, U.S.Pat. Nos. 5,055,119, 5,034,276 and 3,473,950 disclose examples of suchchemical treatments. Typically, with chemical treatment of some of theprior art, solvents are used to lower the viscosity of the chemicaltreatment to facilitate wetting of the glass fibers. The solvent issubstantially unreactive with the other constituents of the chemicaltreatment and is driven out of the chemical treatment after the wettingof the glass fibers. In each process for applying solvent-based chemicaltreatments, an external source such as heat can be used to evaporate orotherwise remove the water or other solvent from the applied chemicaltreatment, leaving a coating of organic material on the glass fibers.With melt-based chemical treatment systems, thermoplastic-type organicsolids can be melted and applied to various fibrous structures. Again,in the area of glass coating, U.S. Pat. Nos. 4,567,102, 4,537,610,3,783,001 and 3,473,950 disclose examples of such melt-based chemicaltreatments of glass fibers. These methods and others have been used inthe prior art to coat various elongated materials including textileyarns, monofilaments, bundles of monofilaments, and fibrous structures.

Supercritical fluids have been used previously to coat elongatedmaterials such as fibers, metals, and the like. However, when suchsupercritical fluids have been used, they have typically been applied byone of a few methods. Several of these techniques involve theapplication of one or more modifying agent by batch soaking in anenclosed chamber. Other methods include processes based upon sprayingfrom a pressurized chamber through a narrow nozzle.

With regard to spray-on deposition, air pressure sprayers have been usedto contain supercritical and near-critical fluids (carriers) containingcoating material. Upon spraying of the fluid onto the substrate, thesupercritical fluid carrier and the coating material leave the highpressure environment and are exposed to a normal atmosphericenvironment. Thus, the supercritical fluid is exposed to low pressureand evaporates, leaving behind the coating material or modifying agent,which is deposited onto, or modifies the substrate, respectively.Examples of typical spray depositions of the prior art include U.S. Pat.Nos. 4,582,731, 4,734,227, 4,734,451, 4,970,093, 5,032,568, 5,213,851,and 5,997,956. Regarding supercritical fluid batch processes, thesubstrate is typically immersed and then the pressure is dropped,depositing the coating. This is usually followed by a drying stage. In arelated embodiment, fluorocarbon polymers can be used to enhancesolubility of polar components in supercritical fluid. However, this isstill a batch process.

Though the use of liquified gas, supercritical fluids, and nearsupercritical liquids and gases have been used to coat solid or otherfibrous substrates in the prior art, none presently known by theapplicant appear to provide a system for modifying substrates,particularly elongated substrates, with multiple modifying agents in asingle continuous system.

SUMMARY OF THE INVENTION

The present invention is drawn to a system configured for applyingmultiple modifying agents to a substrate. The system comprises a firstprocessing chamber configured for applying a first modifying agent to asubstrate and a second processing chamber configured for applying asecond modifying agent to the same substrate. The modifying agents canbe applied in series, one after the other as part of a continuous feed.A first interstitial seal is disposed between the first processingchamber and the second processing chamber. This interstitial seal isoptional and can be configured for substantially separating fluidspresent in each processing chamber. A pair of end seals are alsodisclosed in relation to the present invention. Specifically, a firstend seal can be disposed adjacent to the first processing chamber, and asecond end seal can be disposed adjacent to the second processingchamber. Each of the end seals are configured for substantiallyseparating the fluids present in each of the processing chambers fromthe surrounding atmosphere. A passageway is provided within the deviceconfigured for passing the substrate through the first end seal, thefirst chamber, the interstitial seal, the second chamber, and the secondend seal in series.

Though not required, at least one expansion chamber can be disposedbetween each of the seals and each of the processing chambers. Forexample, with respect to the first processing chamber, at least one sealcan be disposed between the first end seal and the first processingchamber and at least one expansion chamber can be disposed between thefirst processing chamber and the interstitial seal. With respect to thesecond processing chamber, at least one expansion chamber can bedisposed between the second end seal and the second processing chamberat least one expansion chamber can be disposed between the secondprocessing chamber and the interstitial seal.

Additionally, a method of continuously modifying an elongated substratewith multiple modifying agents can comprise the steps of: a) providing acontinuous treatment apparatus comprising a first processing chamberconfigured for applying a first modifying agent to the substrate, asecond processing chamber configured for applying a second modifyingagent to the substrate after the first modifying agent is applied to thesubstrate, wherein each of the first and second modifying agents aresubstantially isolated from the other; and b) continuously passing thesubstrate through the first processing chamber and the second processingchamber in series, such that the first modifying agent acts upon thesubstrate and the second modifying agents subsequently acts upon thesubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawing which illustrates an embodiment of theinvention:

FIG. 1 is a schematic representation of an embodiment of the system ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

Before the present invention is disclosed and described, it is to beunderstood that this invention is not limited to the particularconfigurations, process steps and materials disclosed herein as thesemay vary to some degree. It is also to be understood that theterminology used herein is used for the purpose of describing particularembodiments only, and is not intended to be limiting as to the scope ofthe present invention. The invention will be limited only by theappended claims and equivalents thereof.

It must be noted that, as used in this specification and the appendedclaims, singular forms of “a,” “an,” and “the” include plural referentsunless the content clearly dictates otherwise.

For the purposes of this document, “substrate” can include any structurethat is elongated along at least one axis including, but are not limitedto textile yarns, monofilaments, bundles of monofilaments fibrousstructural materials, fibrous high-strength materials, fibrousconstruction materials, and fibrous engineered materials includingoptical fibers, filaments, cables, fiberglass, glass fibers, ceramicfibers, graphite fibers, composites fibers, metal fibers and wires. Suchstructures can be constructed of metals, alloys, inorganicorganometallics, salts, minerals, structural polymers, single-strandpolymers, filamentous polymers, and the like. If the substrate is otherthan wire is like in shape, ie., elongated along one axis andnon-equidimensional along the plane perpendicular to the direction oftravel through the system (sheet-like, U-shaped, etc.), then thepassageway of the system can be configured accordingly to accept such asubstrate. Otherwise, the passageway can be configured to acceptcylindrical substrates.

“Supercritical fluid” shall be defined as a carrier or acarrier/chemical modifier Mixture which is at a temperature above itscritical temperature.

“Near-critical fluid” includes conditions where the carrier is either ator below the critical temperature or pressure for the carrier (orcarrier with the chemical modifier) wherein the properties of themixture are at a state where they begin to approach those of asupercritical fluid. Near-critical fluid can further be divided intosubcatagories “near-critical gas phase” and “near-critical liquid phase”depending on the state that the fluid is in. “Neat-critical gas phase”exists at pressures either less than or equal to the critical pressureand less than the bubble point pressure with temperatures somewhat belowto above the critical temperature (0.9T_(c) and above). “Near-criticalliquid phase” is defined as the phase that exists at temperatures eitherless than or equal to the critical temperature and pressures eithergreater than or equal to the bubble point pressure of the carrier and/orthe carrier and the chemical modifier.

“Liquefied gas” includes all gases that are at a temperature and/orpressure where they are in a liquid state, but can readily be changed toa gaseous state by altering the temperature or pressure. “Superheatedfluid” shall be defined as all liquids that can readily be changed to agaseous state by reducing the pressure. Typically, this is a liquidwhich is heated above the temperature at which a change of state wouldnormally take place without any change of state having occurred. Anexample would be pressurized water above 100° at sea level.

“Superheated liquid” shall be defined a liquid, which is heated abovethe temperature at which a change of state would normally take place,without said change of state having occurred. An example would bepressurized water above 100° C. “Modifying agent” and “modifyingcomposition” can be used interchangeably and shall include any substanceused for chemical or non-chemical modification of a substrate. Thus,organic coatings, inorganic coatings, reactive coatings, sensorcoatings, catalytic coatings, conductive coatings, material expanders,impregnators, extractors, surface functionalizers, and other modifiersare included within the present definition.

“Fluid” or “critical fluid” used generically shall include supercriticalfluid, near-critical fluid, superheated fluid, superheated liquid, andliquefied gas, unless the context clearly dictates otherwise.

“Treatment mixture” or, “process fluid” shall include any mixture of acarrier (preferably a fluid carrier as defined above) and a modifyingagent.

Turning now to FIG. 1, a'schematic representation of an embodiment of asystem of the present invention is shown. The device is definedgenerally by a housing 8 which is capable of substantially retainingtreatment mixtures, seal fluids, and other fluids used in the device.Baffles 10 are shown which define a passageway 12 within the housing 8.The passageway 12 is preferably slightly larger than the substrate 32which is passed through the device. Depending on the shape of theelongated substrate 32, the shape of the passageway 12 can be configuredaccordingly. The device of the embodiment shown has four separateprocessing chambers 14,16,18,20 which can each independently serve aseparate function from the other chambers.

Processing chamber 14 is a venturi chamber that can be used tosubstantially prepare the substrate passing through the device forfurther modification. A first injector 22 is shown that is positioned ata tangential angle such that process fluids injected therein are causedto swirl around a substrate 32. Appropriate chemicals or substratemodifiers can be used to carry out the function of substratepreparation. For example, chamber 22 can be configured to clean thesubstrate, remove chemical compositions from the substrate, initiatereactions, etc.

Processing chamber 16 is a chamber capable of containing a fluid formodifying the substrate as it passes through the chamber continuously. Asecond injector 24 can be used to fill the chamber with a process fluidor treatment mixture while maintaining a specific temperature and/orpressure ideal for the desired modification of the substrate. Though notrequired, pressures and temperatures can be used to createsupercritical, near-critical, superheated, and liquified gas conditionsof a carrier and/or a modifying agent. Alternatively, this chamber 16can be used for conventional contact processing. However, the substrateis not merely modified at one time, but is continuously passed throughthe contacting chamber and is modified continuously as it travelsthrough the chamber.

Processing chamber 18 shows an impregnation chamber. Thus, injector 26is positioned in close proximity to the passageway (and thus, thesubstrate) such that high pressure impregnation through injector 26 canbe effectuated.

Processing chamber 20 is configured similarly to processing chamber 14,but can be used for a different function. For example, as processingchamber 14 was used for a cleaning purpose, processing chamber 20 can beused to coat the substrate with a modifying agent. Injector 28 can beused to inject a treatment mixture comprised of a carrier, e.g.,supercritical, near-critical, superheated, or liquefied gas, and amodifying agent into processing chamber 20. By injecting the treatmentmixture in at a tangential angle into a constricted region 30 ofprocessing chamber 20, the fluid can swirl around the continuoussubstrate through the constricted region 30. Thus, upon a pressure drop,the modifying agent can be deposited onto or into the substrate.

Each of the processing chambers 14,16,18,20 are substantially isolatedfrom the exterior atmosphere 34 by a pair of end seals 36 a,b.Additionally, the processing chambers are substantially isolated fromone another by three interstitial seals 38 a,b,c. Preferably, the endseals 36 a,b and the interstitial seals 38 a,b,c are pressurized by afluid such as a gas. A fluid compressor 40 is used to regulate theamount of pressure maintained in the end seals 36 a,b and interstitialseals 38 a,b,c. Though this embodiment shows a connected network ofconduits 44 to pressurize all the seals, each seal can be individuallypressurized or pressurized in groups by additional fluid compressors oruse of pressure regulators.

Though not required, each of the processing chambers 14,16,18,20 areseparated from their nearest seals by expansion chambers 46 a-1. Theseexpansion chambers allow for better control of pressure and temperaturebetween the processing chambers and the interstitial and end seals aswell as facilitate the removal of excess processing chamber fluids fromthe device. For example, if processing chamber 14 is a high pressurechamber, and the surrounding atmosphere 34 is one atmosphere, threeexpansion chambers, as shown, can provide adequate pressure increasefrom the exterior atmosphere to the high pressure found in processingchamber 14. Thus, expansion chamber 46 a can have a lower pressure thanthe expansion chamber 46 b, which can have a lower pressure thanexpansion chamber 46 c. Thus, the fluid pressure found in end seal 36 aneed only be slightly greater than the pressure found in expansionchamber 46 a in order to substantially prevent leakage of processingchamber fluids into the surrounding atmosphere. Though three expansionchambers 46 a,b,c are shown between processing chamber 14 and end seal36 a, more or less may be required depending on the application andpressure requirements of the specific application. The same is true forall of the expansion chambers 46 a-1. For example, only one expansionchamber is shown between each interstitial seal 38 a,b,c and eachchamber 14,16,18,20. However, more than this or none may be used,depending upon the application.

With respect to the end seals, prior to the substrates entry or exitfrom the device to normal atmospheric pressure (or other exteriorpressure conditions), a smoother pressure transition from the pressureinside the device to the pressure outside the device can be effectuatedwith the use of expansion chambers 46 a,b,c,j,k,l. Additionally, withsome applications (as shown with respect to processing chamber 16),heaters 48 can be used to maintain or change temperatures as needed.Thus, by controlling the processing chamber pressures and temperature ineach individual chamber, and by substantially separating the chamberwith seals, each process application can have its own unique set ofpressure and temperature conditions.

Each individual chamber and associated expansion chambers can also haveits own collection or extraction chamber 50 a-d. This is due to thesubstantial isolation provided by the end seals 36 a,b and theinterstitial seals 38 a,b,c. For example, with respect to processingchamber 20, collection chamber 50 d provides a location for collectionof seal fluids that may leak from end seal 36 b or interstitial seal 38c into the expansion chambers 46 i,j,k,l. Additionally, process fluids,i.e., treatment mixtures, that may leak from processing chamber 20 intothe expansion chambers 46 i,j,k,l can also be collected in collectionchamber 50 d. A recycling conduit 52 is shown between collection chamber50 d and injector 28 indicating that the process fluids containingunused modifying agents can be recycled for further use. Collectionchambers 50 a,b,c can be configured to function similarly.

Additional optional features can include a pressure regulator 54 forregulating the pressure in any of the chambers. In the embodiment shown,a pressure regulator is shown which regulates the pressure of end seal36 b. Additionally, variable control of the speed of the substrate 32trough the device can be controlled by a substrate feed controller 56which is represented schematically.

With these figures in mind, the present invention is drawn to a systemconfigured for applying multiple modifying agents to a substrate,substantially isolated from a surrounding environment. The systemcomprises a first processing chamber configured for applying a firstmodifying agent to a substrate and a second processing chamberconfigured for applying a second modifying agent to the same substrate.The modifying agents are typically applied in series, one after theother in a continuous feed system. A first interstitial seal canoptionally be disposed between the first processing chamber and thesecond processing chamber. This interstitial seal can be configured forsubstantially separating fluids present in each chamber from oneanother. A pair of end seals are also disclosed in relation to thepresent invention. Specifically, a first end seal can be disposedadjacent to the first chamber and the second end seal can be disposedadjacent to the second chamber. Each of the end seals are configured forsubstantially separating the fluids present in each of the chambers fromthe surrounding atmosphere. A passageway can be configured within thedevice for passing the substrate through the first end seal, the firstchamber, the interstitial seal, the second chamber, and the second endseal in series.

Though not required, it is preferred that at least one expansion chamberbe disposed between each of the seals and each of the processingchambers. For example, with respect to the first processing chamber, atleast one seal can be disposed between the first end seal and the firstprocessing chamber and at least one expansion chamber can be disposedbetween the first processing chamber and the interstitial seal. Withrespect to the second processing chamber, at least one expansion chambercan be disposed between the second end seal and the second processingchamber and at least one expansion chamber can be disposed between thesecond processing chamber and the interstitial seal.

Though two processing chambers are disclosed above, more than twochambers can be provided for certain functions. However, if a thirdprocessing chamber is added, is an additional interstitial seal canpreferably also be added to keep the third processing chambersubstantially separate from the other processing chambers. Thus, in oneembodiment, a second interstitial seal and a third processing chambercan be disposed between the second processing chamber and the second endseal. If a fourth processing chamber is desired, such as that shown inFIG. 1, a third interstitial seal and a fourth processing chamber can beadded and disposed between the third processing chamber and the secondend seal.

As stated, each processing chamber can be configured to functioncompletely separately from other processing chambers. For example, oneprocessing chamber can functionalize a surface of a substrate, and asecond processing chamber can apply a coating onto that functionalizedsurface. Therefore, different functions can occur in each chamber.Exemplary processing chamber functions can include venturi applicationchambers, contacting chambers, impregnation chambers, cleaning chambers,chemical reaction chambers, absorption chambers, adsorption chambers,and desorption chambers, to name a few. These chambers can be shaped orconfigured appropriately for a given application.

To illustrate one example, a modifying agent can be applied to asubstrate in one or more of the processing chambers by continuouslypassing the substrate through the passageway within the first processingchamber wherein the processing chamber comprises a first region, asecond region, and a constricted medial region between the first regionand the second region. The processing chamber can be further configuredto accept a treatment mixture into the constricted medial region of thepassageway during movement of said substrates through the processingchamber. The treatment mixture can further be comprised of a modifyingagent in a carrier medium wherein the carrier medium is selected fromthe group consisting of a supercritical fluid, a near-critical fluid, asuperheated fluid, a superheated liquid, and a liquified gas, such thatthe modifying agent will separate from the carrier medium upon apressure drop when the mixture is introduced into the constricted medialregion of the passageway. Thus, the modifying agent can be applied tothe substrate to produce a modified substrate. In this embodiment, theinjector can introduce the treatment mixture at a tangential angle suchthat the treatment mixture is introduced to the substrate at or near theconstricted medial region and as the mixture swirls around thesubstrate. Such a configuration can be used to apply the modifying agentto the substrate in either a co-current manner, i.e., substrate movementin the, direction of the treatment mixture injection, or acounter-current manner, i.e, substrate movement in the oppositedirection of the treatment mixture injection.

The injector can be configured to inject the process fluidstangentially, pendicularly, or at any other functional angle. Forexample, a tangentially angled injector could be used in a chamberhaving two larger opposing regions, separated by a constricted medialregion. Additionally, multiple injectors can be used to ensure that allsurfaces of the non-equidimensional substrate can be appropriatelymodified. Alternatively, a perpendicular injector at close proximity toa substrate could be used to impregnate the substrate with higherpressure injections. In another embodiment, the processing chamber canutilize a treatment mixture comprised of the modifying agent and acarrier for applying the modifying agent, wherein the carrier isselected from the group consisting of supercritical fluid, near-criticalfluid, superheated fluid, superheated liquid, and liquefied gas.

Though the use of supercritical fluid, near-critical fluid, superheatedfluid, superheated liquid, and liquified gas applications have beendescribed with respect to a venturi chamber, this is not the onlyapplication where the use of such fluids can be effective in themodification of a substrate. Any chamber configuration can be used withsuch fluids, provided the conditions are right to modify a substrate asis desired.

As stated, injectors can be used to infuse treatment mixtures or otherprocess fluids into. the processing chambers. The injector can beconfigured to inject the process fluids tangentially, perpendicularly,or at any other functional angle. For example, a tangentially angledinjector could be used in a chamber having two larger opposing regions,separated by a constricted medial region, such as in a venturi or othersimilarly configured chamber. Alternatively, a perpendicular injector atclose proximity to a substrate could be used to impregnate the substratewith higher pressure injections. In one embodiment, whether or not aventuri chamber as described is used, at least one of the firstprocessing chamber and the second processing chamber can utilizes atreatment mixture comprised of the modifying agent and a carrier forapplying the modifying agent, wherein the carrier is selected from thegroup consisting of supercritical fluid, near-critical fluid,superheated fluid, superheated liquid, and liquefied gas.

Extraction or collection chambers can be fluidly coupled to each of theprocessing chambers for periodically or continuously removing unusedmaterial, i.e., seal fluids, carrier, and/or modifying agents, from theprocessing chambers. Because the end seals and the interstitial sealssubstantially separate the fluids from each processing chamber, it ispreferred that each processing chamber have its own extraction orcollection chamber. If expansion chambers are present, then thecollection chambers can be fluidly connected to the processing chambersthrough the expansion chambers. If desired, the fluids collected in thecollection chambers can be recycled for further use. In some instances,a further processing step can occur before reusing any treatment mixturecollected as may be ascertained by one skilled in the art.

The end seals and the interstitial seals can be gas (or other fluid)filled seals. However, gas filled seals are not the only functionalseals that can be used. For example, these seals can simply beconfigured as a physical constriction or other barrier that isfunctional with the present system. If a gas filled seal is used,exemplary gases for use can include air, carbon dioxide (CO₂), nitrogen(N₂), helium, argon, nitrogen dioxide (NO₂), or other compatible processsolvents or fluids. In one embodiment, the gas used in the seals can beessentially inert to the modification process that is occurring in thenearby processing chambers. However, the seals can also be used asbuffer zones between processing chambers. Additionally, any parametercan be used to separate the chambers such as temperature, pressure, orchemical and solvent selection. Multiple fluid filled seals can eitherbe controlled by a single fluid compressor, or each seal (or groups ofseals) can be individually controlled by its own compressor, pressureregulator, or combination of compressor and pressure regulator.

As mentioned, the present device utilizes multiple application chambersor cells to each independently modify a substrate in a continuoussystem. Depending on the size or configuration of the substrate, thepassageway within the chambers are sized slightly larger than thesubstrate that passes through the device to minimize the amount ofprocess fluids or chemical composition that can pass from one chamber tothe next. For example, as the substrate passes from one chamber to thenext, process fluids can leak into the adjacent chamber(s). The amountof process fluid that leaks into adjacent chamber(s) is controlled bycontrolling the pressure in the adjacent chamber(s). This can beaccomplished by pressure loss from the flow of fluid from one chamber tothe next or by removal of excess process fluid from the adjacent chamberfor recycle. Most of the processing chambers of FIG. 1 show only oneadjacent expansion chamber. However, multiple adjacent expansionchambers, each controlled at a specific pressure in a similar method asdescribed above, may be used to better control the pressure drop fromone chamber to the next within the device as required by the specificapplication. Additionally, FIG. 1 shows three expansion chambers and aseal chamber between the fourth processing chamber and the exteriorenvironment. However, more or less may be required depending on theapplication and pressure requirements of the specific application. Thus,prior to entry or exit from the device to normal atmospheric pressure(or other desired exterior pressure), a smoother pressure transitionfrom the pressure inside the device to the pressure outside the devicecan be effectuated. As mentioned, with some applications, heaters can beused to maintain temperatures in a specific chamber. Control of chamberpressures and temperature allows each process application to have itsown unique set of pressure and temperature conditions.

In the area of textiles, a system for dying or sizing textile yams hasbeen disclosed that departs from typical batch processes previouslyknown. Specifically, U.S. Pat. No. 5,709,910, the entire teachings ofwhich are incorporated herein by reference, discloses methods forapplying textile treatment compositions to textile materials. Thissystem comprising a conduit member which includes a passageway having afirst end, a second end, and a medial portion with a constricted(narrowed) region. The passageway may include at least one baffle havingan opening therethrough. In the system, a yarn strand is then movedthrough the passageway. A sizing agent or dye is dissolved in asupercritical fluid or liquified gas which is thereafter introduced intothe constricted region. As the supercritical fluid or liquified gas isforced through the constricted region, the pressure drops and thesupercritical fluid or liquified gas changes in properties such thatdelivery of the treatment dye or sizing agent to the yarn iseffectuated. The textile strands. or yarn that may be sized or dyedinclude any textiles yarns such as cottons, linens, polyesters, nylons,rayons, cotton blends, and the like. The textile yarns disclosed thereinare lower strength yarns that are comprised of a series of short strandfibers that are spun together to form longer yarn products. Thus, strayfibers are inevitable and thus, provides the need for the use of sizingagents and lubricants, described therein. The temporary lubricant actsto reduce the number of stray fibers that may be damaged by any highspeed equipment used in the process of preparing textiles, as well asreduce the friction between textile fibers during weaving. An additionalfunction can include the strengthening of the yarn. Though such a systemand method have been shown to be effective for the sizing and dying ofyarns, no device or method is currently known that utilizes at least twochambers which act independently of one another in a continuous system.Thus, with respect to textile yarns, a first chamber could be used todye the substrate, and a second chamber could be used to size thesubstrate, all in one continuous system.

This system, depending on the specific chamber configuration, allows forthe use of enhanced chemical and physical properties of fluids undersupercritical, near-critical, superheated, and liquified gas conditions,including solvating power, to treat various substrates in a continuous,without the use of such structures as nip rollers. The device upon whichthe process is based also allows for the recovery of process energy andfluids to minimize waste.

The chemical compositions that can be applied with the system of thepresent invention include both organic and inorganic materials includingvarious chemical reagents, monomers, polymers, etc. These chemicalsinclude, but are not limited to, various types of organic compounds andpolymeric materials including acrylates, acrylic acid monomers, acrylicacid polymers, salts of acrylic acid copolymers, salts of polyacrylicacid, polyacrylates, polyvinyl chlorides, polyvinyl acetate, polyvinylalcohols, cellulose derivatives, alginates, gums and starches,polyamides, polyimides, urethanes, polyurethanes, synthetic and naturalresin varnishes, lacquers, polyphosphazenes; polyesters, polystyrenes,silicones, epoxies, fluoropolymers, etc. Chemical materials can beapplied individually, sequentially, or as mixtures.

Virtually any structure can be coated or modified as described herein,provided the coating is functional with the substrate. Specifically,substrates can include continual or finite structures such as textileyarns, monofilaments, bundles of monofilaments, fibrous structuralmaterials, fibrous high-strength materials, fibrous constructionmaterials, and fibrous engineered materials including optical fibers,filaments, cables, fiberglass, glass fibers, ceramic fibers, graphitefibers, composites fibers, metal fibers and wires. Such structures canbe constructed of metals, alloys, inorganics, organometallics, salts,minerals, structural polymers, single-strand polymers, filamentouspolymers, and the like. If the substrate is other than wire-like inshape, i.e., elongated along one axis and non-equidimensional along theplane perpendicular to the direction of travel through the system(sheet-like, U-shaped, etc.), then the passageway of the system can beconfigured accordingly to accept such a substrate. Otherwise, thepassageway can be configured to accept cylindrical substrates.

Turning to an individual discussion of the various type of substratemodifications that can occur, various modification methods areexemplified. With respect to the present invention, many of theseprocess or substrate modification types described relate to singleprocess chamber modifications, though any of these single processchamber modifications can be used in either the first and/or the secondprocess chamber within the system of the present invention.

The process parameters used to modify a substrate, e.g., apply acoating, are highly dependent upon the modification material and theparticular solvent used as the carrier fluid. Temperature and pressure,time of fluid exposure to the modifying material, and factors liketurbulence, ultrasound, mechanical mixing, etc. affect the solubility ofthe modifying material and rate at which the modifying material can bedissolved into the fluid. A suitable range for temperature and pressureis that defined by the following: 0.9T_(c)≦T≦2T_(c) where T and T_(c)are expressed in degrees Kelvin, and 0.1P_(c)≦P≦20P_(c) where P andP_(c) are expressed in any suitable pressure units.

The first equation states that the useable operating temperature (T) forthe solvent has a value equal to, or greater than 0.9 times the value ofthe critical temperature (T_(c)), and less than or equal to 2 times thecritical temperature. The second equation similarly states that theuseable operating pressure (P) for the solvent has a value equal to, orgreater than 0.1 times the value of the critical pressure (P_(c)), andless than or equal to 20 times the critical pressure.

In general, it is desirable to saturate the fluid with the modifyingmaterial or dissolve an amount close to the saturation limit; but anylevel of solubilization will achieve the effect of substratemodification. In practice, this is highly dependent upon the choice ofsolvent and solute, and the range can be quite extensive. Two examplesare given that illustrate this feature.

To impregnate poly(methyl methacrylate) (PMM) with pyrene to make achemical sensor, one would dissolve 0.001 mole % pyrene in criticalcarbon dioxide (within the temperature and pressure conditionsestablished above) and expose the PMM to the critical solution. Notethat this is an extremely dilute solution and well below saturation. Anexample illustrating the opposite extreme where the solute is at 100mole % (i.e. the solute is the solvent) would be the coating of anoptical fiber with a poly-fluorinated hydrocarbon (PFH). In thisexample, one would bring the PFH to within the conditions describedabove (2 equations) and expose the optical fiber to the solvent/soluteto achieve the desired coating.

Useable concentrations for other solvent/solute mixtures areintermediate between, the values given above and are largely governed bythe solubility of the solute in the particular critical fluid. The rangeextends from those that have very small solubility to those that arecompletely miscible. An example of the first is given above, while anexample of the latter would be the use of tributyl phosphate (TBP)dissolved in supercritical carbon dioxide to be used as adecontamination solvent. In this case the solvent (CO₂) can be used insmaller proportion than the TBP and even below 10 mole percent.

With respect to organic and inorganic coatings, functional coatingsintended to impart some physical attribute to the substrate being coatedare included. Some physical attributes can include imparting corrosionresistance, degradation resistance, abrasion resistance, hardness,lubricity, light (or other radiation) reflective or absorptiveproperties, ductility, elasticity, material thickness, magneticsusceptibility, radiation degradation resistance, stress relief orresistance, thermal tolerance, and other similar attributes. Anotherfunction might be to encapsulate the coated material to restrict ormodify the movement of chemicals across the coating. The nature of thesecoatings is that they are superficial and comprise a coating or barrierbetween the coated material and the external environment.

Organic modifiers or coatings can be comprised in majority or entirelyof organic materials. Such organic coatings can include occludedparticles or co-deposited organic materials or inorganic materials. Inone embodiment, polystyrene in critical fluid acetone can be applied toglass optical fibers to increase durability of the fibers. In anotherembodiment, varnish in a critical paint thinner can be applied to copperwires for motor windings. In these and other embodiments, urethane orlatex with or without nano-sized titania can be applied during thecoating process or subsequent to coating and prior to drying of theorganic, respectively, to form corrosion resistant materials or solidsupported catalysts.

Another coating type includes inorganic coatings. These coatings can becomprised of a majority or entirely of inorganic or non-organicmaterials, though occluded or co-deposited organic materials or otherinorganic materials can also be present. Examples of inorganic coatingsinclude metal and non-metal oxides, silicon, sulfur, or phosphorus-basedpolymers that may include dopants comprised of metals, organometallics,inorganics, hetero-atomic organics, minerals, or salts. In one example,silicone in a fluid petroleum ether can be applied to graphite fibers toimpart a dielectric coating.

Reactive coatings refers to functional coatings intended to impartchemical reactivity or a specific chemical nature to various substrates,particularly with respect otherwise inert or un-reactive materials. Manycoatings can be both reactive or non-reactive depending upon theenvironment surrounding the coating or the specific application for thecoating. For example, in the prior art, polyvinyl alcohol has been usedas an un-reactive coating to temporarily lubricate textile fibers.However, as part of the present invention, polyvinyl alcohol can be usedas a permanent coating to coat an optical fiber so it can behave as asorbant coating that changes the optical properties of the fiber underdiffering chemical conditions. Sensor coatings are those coatings thatinteract with the surrounding environment in a manner that changes oneor more of their chemical or physical properties. This sensorcharacteristic can be used to sense changing conditions in anenvironment. Sensor materials can be reactive or non-reactive (butinteractive) with the environment. As an example of a non-reactive(interactive) coating, pyrene in fluid toluene (carrier) can be appliedto glass optical fibers to affect the light transmittancecharacteristics of the fiber in the presence of explosives. As anexample of a reactive coating, polysulphones can be applied via criticalfluid toluene or methylene chloride, to optical fibers such that thesulfones react with acidic or basic media and change the lighttransmitting properties of the fiber.

Catalytic coatings, or coatings that interact chemically with thesurrounding environment in a manner wherein the coating behaves as acatalyst in a chemical reaction, can also be formed. An example of acatalytic coatings includes the dissolving of silver chloride and abeta-diketone in fluid carbon dioxide. Thereafter the mixture isdirected onto a substrate in the presence of hydrogen. Silver metal willbe deposited onto the surface of the substrate and can behave as acatalyst. Additionally, chloroplatinic acid can be dissolved in a fluidwater to coat a carbon fiber in accordance with the principals of thepresent invention. After such a deposition, sodium borohydride can beapplied to reduce the platinum to the metallic state. Thus, the coatingcan be used as a catalyst. Additionally, other salts, solvents,complexing agents, substrates and reducing agents can yield similarresults.

Conductive coatings refers to functional coatings that are thermally orelectrically conductive. This includes coatings that are metallic,inorganic, organic, or polymeric in nature and/or composition. Metalcoatings may be applied directly by coating the metal onto a substrate,or formed indirectly by applying a reactive coating containing the metalin a chemical state that can later be changed to make the coatingconductive. For example, a substrate can be coated with ametal-containing flux (e.g. lead in zinc chloride) in fluid alcohol,after which, the coating can be heated or exposed to a chemicalenvironment that would reduce the metal-containing flux to the metallicstate (lead in this case). This process would produce “tinned”substrates suitable for soldering applications. Alternatively, asubstrate can be coated with a sulfonated polystyrene in fluid acetone.Thus, when exposed to water, it will become electrically conductive. Itwould be appreciated to one skilled in the art that the use of othermetal salts, fluxes, solvents, polymers, etc., will give similarresults.

With the present system, the need to utilize multiple-passes to applymore than one coating, for example, is diminished because eachprocessing chamber can be configured to act independently of the otherchambers. However, if desired, multiple pass applications through thesystem disclosed herein are also within the scope of the presentinvention.

Generally, there are two broad categories of substrate modifications(outside of coating) that can be effectuated which include physical andchemical modification Physical modifications refers to thosemodifications that are primarily characterized by, or made to enhance,physical characteristics of the substrate through application of theinvention, but not through applying a coating per se. Examples of whichare included herein.

Expanded materials include substrates that can be passed through adevice like unto the device described herein under fluid pressure,whereupon exiting a higher the pressure region and entering anotherlower pressure region can cause rapid expansion of the substrate as afluid is expanded out of the substrate. An example would be to pass aPlexiglas [poly(methyl methacrylate)] substrate through the devicepressurized with fluid methylene chloride and hexane, whereupon exitinginto a lower pressure region will cause expansion of the Plexiglas.

With regard to impregnation, suspended particulate material can beforced to impregnate a substrate by applying the particulate underpressure. as a suspension in a fluid through a constriction, venturi, orother type of orifice that is at a near-contact distance from thesubstrate. An example would be to use nano-sized graphite particulatesuspended in fluid mineral oil that is then applied under pressure toimpregnate low-density polyethylene. Alternatively, a metal salt can bedissolved into a fluid and applied to a substrate that has somesolubility in the fluid. Then the metal salt can also be converted tothe metallic state by appropriate chemistry (reduction or oxidation),resulting in the metal being impregnated into the substrate. An exampleof this would be to dissolve silver chloride into fluid water/acetonemixture and apply this mixture to a poly(methyl methacrylate) substrate.Next, by contacting the coating with a hydrogen or sodium borohydride,reduction will occur and reduce the silver to the metallic state whileimbedded within the substrate.

An example wherein multiple chambers are used to yield an impregnatedsubstrate, i.e., PVC, is also shown below. First, critical methylenechloride is applied to PVC (polyvinyl chloride) in a first chamber. In asubsequent chamber (or in a single venturi type chamber) the pressure isreduced causing an expansion to occur. Next, a fluid mixture of silverchloride and a beta-diketone in fluid carbon dioxide is added to thesubstrate in a subsequent chamber. After this step, hydrogen is exposedto the substrate to reduce the silver to the metallic state while insideof the substrate. Alternatively a polyvinyl chloride substrate can beexposed to fluid methylene chloride in a chamber followed by expandingit in a subsequent chamber where the pressure is reduced. Next, bypassing the substrate through a reduced-size orifice in which thesubstrate is pressure-injected with particulate silver or a suspensionof particulate silver in a fluid mineral oil suspensions, the particularsilver is deposited to the substrate. The substrate can then remainunmodified after this last process to yield a silver impregnatedpolyvinyl chloride substrate or it can be further processed andcontracted by introducing the substrate in yet another chamber to afluid methylene chloride whereafter the substrate would proceed throughthe expansion chambers where the pressure is gradually reduced. Thislatter process would yield an impregnated PVC substrate where thesurface of the substrate will have been closed over the impregnatedparticles to some varying degree.

With respect to chemical modification, the chemical characteristics ofthe substrate can be altered or enhanced. Examples include extractionand surface functionalization. Extractions apply to the removal of somecomponent such as a soluble component, from the substrate. An examplewould be to remove a plasticizer, monomer units, or unwanted oligomersfrom polymer substrates. One application would be to extract unwantedcontaminants from soil or other environmental matrices such as removingcrude oil from sand and soils where spills have occurred by applyingalcohol or hexane in fluid form to a soil as it passed through thedevice. With respect to surface functionalization, a process andresultant state wherein the surface of the substrate is chemicallymodified can be accomplished. An example includes the passing of acellulose substrate through a device described herein and expose it toone or more of fluid nitric acid, phosphoric acid, sulfuric acid, etc.to produce the nitrated, phosphated, sulfated, etc. cellulose,respectively. The nitrated cellulose could be used in explosives, whilethe phosphated or sulfated cellulose could be used as ion-exchangematerial.

In addition to the coatings and/or chemical modifications describedherein, even new materials can be made by combining the individualcomponents, or combinations of components inside the supercritical orfluid region of a device of the present invention. Synthesis of thematerials can occur as a singular processing which the material is notcoated onto any substrate and exits the device in the general shape ofthe exiting orifice. Alternatively, new materials could be made in asimilar manner, but coated onto a substrate passing through the device.In the latter case, the new material can be added to the substratecoating, impregnation, etc., in a similar manner to the other processesdescribed herein. Additionally, polymer synthesis is also possible byusing a device such as that described herein. An example includes thesynthesis of polystyrene(co-methyl methacrylate) where the individualcomponents of styrene and methyl methacrylate are initially dissolved influid acetone and injected into one of the chambers of the device andallowed to mix. Upon exiting the chamber, the acetone is removed andbenzoyl peroxide is injected to initiate the polymerization. Next, thepolymer can be extruded through the exiting orifice of the device.Composites, which are those materials that are composed of more than onematerial and are solid in the finished state, mutually insoluble, anddifferent in chemical nature can also be made. An example of a compositethat can be made in this device is the coating of a graphite fiber withPlexiglas. Plexiglas can be dissolved in fluid methylene chloride andintroduced into a chamber through which the graphite fiber is moving. Inthis embodiment, the Plexiglas will deposit onto the fiber and adhere tothe fiber upon exiting the chamber where the solvent can be removed.

The current processes will provide coatings and other modifications withsuperior properties because of improved adhesion, bonding, and chemicalreactivity or extraction. Exposure to the fluids during the applicationprocesses can also exert a cleaning influence on a substrate, removingsurface contaminants that detrimentally affect the ultimate propertiesof the final product. It is anticipated that these processes can reducefailure rates and defects, and products with superior properties, suchas tensile strength can be produced. Additionally, these processesprovide opportunities for application of thermally labile or otherwisesensitive chemical compositions to a variety of substrates.

Additionally a method of continuously modifying an elongated substratewith multiple modifying agents is disclosed comprising the steps ofproviding a continuous treatment apparatus comprising a first processingchamber configured for applying a first modifying agent to the substrateand a second processing chamber configured for applying a secondmodifying agent to the substrate after said first modifying agent isapplied to said substrate, wherein each of the first and secondmodifying agents are substantially isolated from the other; andcontinuously passing the substrate through the first processing chamberand the second processing chamber in series such that the firstmodifying agent acts upon the substrate and the second modifying agentsubsequently acts upon the substrate.

While the invention has been described with reference to certainpreferred embodiments, those skilled in the art will appreciate thatvarious modifications, changes, omissions and substitutions can be madewithout departing from the spirit of the invention. It is intended,therefore, that the invention be limited only by the following claimsconstrued as broadly as applicable law allows including all properequivalents thereof.

We claim:
 1. A system configured for applying multiple modifying agentsto a continuous substrate, substantially isolated from a surroundingatmosphere, comprising: a first processing chamber configured forapplying a first modifying agent to the continuous substrate, said firstprocessing chamber comprising a first region, a second region, and aconstricted medial region between said first region and said secondregion, said first processing chamber being further configured to accepta first treatment mixture into said constricted medial region duringcontinuous movement of said continuous substrate through said firstprocessing chamber, said first treatment mixture comprising the firstmodifying agent in a first carrier medium, said first carrier mediumbeing selected from the group consisting of a supercritical fluid, anear-critical fluid, a superheated fluid, a superheated liquid, and aliquified gas, such that said first modifying agent separates from saidfirst carrier medium upon a pressure drop when said first treatmentmixture is introduced into said constricted medial region, applying saidfirst modifying agent to said continuous substrate; a second processingchamber configured for applying a second modifying agent to saidcontinuous substrate after the first modifying agent is applied to saidcontinuous substrate; a first end seal disposed adjacent to the firstprocessing chamber configured for substantially isolating fluids presentin the first processing chamber from the surrounding atmosphere; asecond end seal disposed adjacent to the second processing chamberconfigured for substantially isolating fluids present in the secondprocessing chamber from the surrounding atmosphere; and a passagewayconfigured for allowing continuous passage of the continuous substratethrough the first end seal, the first processing chamber, the secondprocessing chamber, and the second end seal in series.
 2. A system as inclaim 1, further comprising a first interstitial seal disposed betweenthe first processing chamber and the second processing chamber,configured for keeping fluids present in each of said processingchambers substantially separate.
 3. A system as in claim 2, furthercomprising at least one expansion chamber disposed between the first endseal and the first processing chamber, and further comprising at leastone expansion chamber disposed between the first processing chamber andthe first interstitial seal.
 4. A system as in claim 3, furthercomprising at least one expansion chamber disposed between the secondend seal and the second processing chamber, and further comprising atleast one expansion chamber disposed between the second processingchamber and the first interstitial seal.
 5. A system as in claim 4,wherein the interstitial seal and the end seals are gas filled seals. 6.A system as in claim 5, wherein said interstitial seal and said endseals are each configured such that gas pressure within each of theseals may be maintained at a level at least slightly greater than thatof an adjacent expansion chamber.
 7. A system as in claim 2, furthercomprising a second interstitial seal and a third processing chamberdisposed between the second processing chamber and the second end seal.8. A system as in claim 7, further comprising a third interstitial sealand a fourth processing chamber disposed between the third processingchamber and the second end seal.
 9. A system as in claim 2, wherein saidfirst processing chamber and said second processing chamber areindependently selected from the group consisting of venturi chambers,contacting chambers, impregnation chambers, cleaning chambers, chemicalreaction chambers, absorption chambers, adsorption chambers, anddesorption chambers.
 10. A system as in claim 2, wherein the secondprocessing chamber is configured to utilize a second treatment mixturecomprising the second modifying agent and a second carrier for applyingthe second modifying agent, wherein the second carrier is selected fromthe group consisting of supercritical fluid, near-critical fluid,superheated fluid, superheated liquid, and liquefied gas.
 11. A systemas in claim 10, further comprising an injector configured for injectingthe second treatment mixture into the second processing chamber.
 12. Asystem as in claim 11, wherein the second processing chamber has anenlarged first region, an enlarged second region, and a constrictedmedial region between said first region and said second region.
 13. Asystem as in claim 12, wherein the injector is tangentially angledtoward the constricted medial region of the second processing chamber.14. A system as in claim 11, wherein the injector is directedessentially perpendicular to the passageway in the second processingchamber.
 15. A system as in claim 14, wherein the injector is positionedin close proximity to the passageway such that the injector canimpregnate the continuous substrate with a high pressure injection ofthe second treatment mixture.
 16. A system as in claim 1, wherein saidsecond processing chamber comprises a first region, a second region, anda constricted medial region between said first region and said secondregion, said second processing chamber being further configured toaccept a second treatment mixture into said constricted medial region ofsaid second processing chamber during continuous movement of saidcontinuous substrate through said second processing chamber, said secondtreatment mixture comprising the second modifying agent in a secondcarrier medium selected from the group consisting of a supercriticalfluid, a near-critical fluid, a superheated fluid, a superheated liquid,and a liquified gas, such that said second modifying agent separatesfrom said second carrier medium upon a pressure drop when said secondtreatment mixture is introduced into said constricted medial region ofsaid second processing chamber applying said second modifying agent tosaid continuous substrate.
 17. A system as in claim 1, wherein thepassageway is configured such that the continuous substrate is passedthrough the passageway co-currently.
 18. A system as in claim 1, whereinthe passageway is configured such that the continuous substrate ispassed through the passageway counter-currently.
 19. A system as inclaim 1, wherein pressure is controlled in at least one of the firstprocessing chamber and the second processing chamber by a pressureregulator.
 20. A system as in claim 1, wherein the temperature iscontrolled in at least one of the first processing chamber and thesecond processing chamber by a temperature regulator.
 21. A system as inclaim 1, further comprising a substrate feed controller configured forcontrolling the speed at which the continuous substrate is passedthrough the system.
 22. A system as in claim 1, further comprising aninjector configured for injecting the first treatment mixture into thefirst processing chamber.
 23. A system as in claim 22, wherein theinjector is tangentially angled toward the medial region of the firstprocessing chamber.
 24. A system as in claim 22, wherein the injector isdirected essentially perpendicular to the passageway in the firstprocessing chamber.
 25. A system as in claim 24, wherein the injector ispositioned in close proximity to the passageway such that the injectorcan impregnate the continuous substrate with a high pressure injectionof the first treatment mixture.
 26. A system configured for applyingmultiple modifying agents to a continuous substrate, substantiallyisolated from a surrounding atmosphere comprising; a first processingchamber configured for applying a first modifying agent to thecontinuous substrate and a second processing chamber configured forapplying a second modifying agent to said continuous substrate after thefirst modifying agent is applied to said continuous substrate, where atleast one processing chamber of the first processing chamber and thesecond processing chamber is fluidly coupled to a correspondingcollection chamber configured for removing unused modifying agent fromthe at least one processing chamber; a first end seal disposed adjacentto the first processing chamber configured for substantially isolatingfluids present in the first processing chamber from the surroundingatmosphere; a second end seal disposed adjacents to the secondprocessing chamber configured for substantially isolating fluids presentin the second processing chamber from the surrounding atmosphere; afirst interstitial seal disposed between the first processing chamberand the second processing chamber, configured for keeping fluids presentin each of said processing chambers substantially separate; and apassageway configured for allowing continuous passage of the continuoussubstrate through the first end seal, the first processing chamber, thesecond processing chamber, and the second end seal in series.
 27. Asystem as in claim 26, wherein the first processing chamber is fluidlycoupled to a first collection chamber and the second processing chamberis fluidly coupled to a second collection chamber.
 28. A system as inclaim 26, wherein at least one expansion chamber is fluidly disposedbetween the at least one collection chamber and the correspondingprocessing chamber.
 29. A system as in claim 26, wherein the first endseal and the second end seal are adjustable to various diameters foraccepting various sized continuous substrates for modification.
 30. Asystem configured for applying multiple modifying agents to a continuoussubstrate, substantially isolated from a surrounding atmospherecomprising: a first processing chamber configured for applying a firstmodifying agent to the continuous substrate; a second processing chamberfor applying a second modifying agent to said continuous substrate afterthe first modifying agent is applied to said continuous substrate; afirst end seal disposed adjacent to the second processing chamber andthe second processing isolating fluids present in the first processingchamber from the surrounding atmosphere; a second end seal disposedadjacent to the second processing chamber configured for substantiallyisolating fluids present in the second processing chamber from thesubstantially separate; a first interstitial seal disposed between thefirst processing chamber and the second processing chamber, configuredfor keeping fluids present in each of said processing chamberssubstantially separate; a collection chamber configured for collecting acarrier and any unused modifying agent from at least one processingchamber of the first processing chamber and the second processingchamber, wherein the at least one processing chamber is configured toutilize a treatment mixture comprising the modifying agent and thecarrier, wherein the carrier is selected from the group consisting ofsupercritical fluid, near-critical fluid, superheated fluid, superheatedliquid, and liquefied gas; and a passageway configured for allowingcontinuous passage of the continuous substrate through the first endseal, the first processing chamber, the second processing chamber, andthe second end seal in series.
 31. A system as in claim 30, furthercomprising a recycling system for recycling the carrier and the unusedmodifying agent collected by said collection chamber.
 32. A deviceconfigured for applying multiple modifying agents to a continuoussubstrate while substantially isolating the continuous substrate from asurrounding atmosphere, comprising: a passageway configured forcontinuous passing a substrate through the system; a first processingchamber configured for applying a first modifying agent to thecontinuous substrate; a second processing chamber configured forapplying a second modifying agent to said continuous substrate after thefirst modifying agent is applied to said continuous substrate; at leastone processing chamber of said first processing chamber and said secondprocessing chamber comprising a first region, a second region, and aconstricted medial region between said first region and said secondregion, said at least one processing chamber being further configured toaccept a treatment mixture into said constricted region of saidpassageway during continuous movement of said continuous substratethrough said passageway within said at least one processing chamber,said treatment mixture comprising the modifying agent in a carriermedium, said carrier medium being selected from the group consisting ofa supercritical fluid, a near-critical fluid, a superheated fluid, asuperheated liquid, and liquified gas, such that said modifying agentseparated from said constricted region upon a pressure drop when saidtreatment mixture is introduced into continuous substrate; at least oneinjector for each of the first and second processing chambers forinjecting the first and second modifying agents into the first andsecond processing chambers, respectively, such that each modifying agentmodifies the substrate continuously; a first interstitial seal disposedbetween the first processing chamber and the second processing chamber,configured for keeping fluids present in each processing chambersubstantially separate; a first end seal positioned adjacent to thefirst processing chamber configured for substantially isolating fluidspresent in the first processing chamber from the surrounding atmosphere;a second end seal positioned adjacent to the second processing chamberconfigured for substantially isolating fluids present in the secondprocessing chamber from the surrounding atmosphere; at least oneexpansion chamber disposed between each processing chamber and itsadjacent end seals and interstitial seal.